The Tylosaurus was an aquatic reptile that roamed the prehistoric seas of FMM UV-32.
In Carnivores Cityscape, the Tylosaurus can be found swimming around in rivers and sewers. If they cannot travel well out of the water, it is unknown how they got into the sewers from the rivers, or even out of the ship. Strangely, it is dead which is not in line with the actual animal. Since it is basically the prehistoric equivalent of a great white shark and a whale, it would be expected to lunge at agents and passing dinosaurs from under the water, although since it has been extinct for millions of years this cannot be known for sure.
Carnivores: Dinosaur Hunter
In Carnivores, the Tylosaurus can be hunted with tranquilizers; it must be killed. In Carnivores 2, it can be hunted with tranquilizers, but it lacks a sleeping animation and sound, meaning it appears to be dead. In the first game, depending upon the Density setting in the Options menu, 1-3 Tylosaurus may appear on the map at any given time. The high-density setting yields only one on the map, while the highest yields 3. However, in the second game, many Tylosaurus roams the map-making hunts with them even riskier, especially on High-Density settings. Spawning in an area with a Tylosaurus close by on the water is often fatal. It also appears on the game's box art.
A possible explanation for why they were able to travel off the ship is because they could have been there beforehand. Since the FMM UV-32 species is not a threat to humans, they could have been imported to Earth colonies from FMM UV-32 to add a little scenery to the rivers and sewers.
This, however, is just a possible inference and is not based on currently known information.
There are animations are well organized as some crocodile and whale as well.
In Carnivores Dinosaur Hunter, The Tylosaurs can be found in rivers and oceans.